Arrangement for determining frame lengths on film strips

ABSTRACT

One or more photoresistors, arranged to detect light passing through the film strip, cause varying signal voltages, the maximum voltages of which are stored and compared with the instantaneous signal voltages to produce a signal corresponding to the format of the film just examined.

I United States Patent 151 3,699,349 Paulus et a1. [4 Oct. 17, 1972ARRANGEMENT FOR DETERMINING [56] References Cited FRAME LENGTHS ON FILMSTRIPS UNITED STATES PATENTS [72] Inventors: Rudolf Paulus; Hans-PeterHuber, 3299 272 1/1967 F k t 250,2191) b th f uru awae a......

Mumch Germany 3,559,253 2/1971 Pandell et a1 ..250/219 LG [73] AsslgneezAgfa-Gevaert Akti ng s ll ha 1,348,566 8/1920 Jenkins ..250/219 FR XLeverkusen, Germany 3,428,817 2/1969 Hofmeister et al. .250/219 LG [22]Filed: v Oct 16, 1970 3,518,440 6/1970 Hanson et a1. ..250/219 D [21]Appl. No.2 81,347 Primary Examiner-Walter Stolwein Attorney-Michael S.Striker [30] Foreign Application Priority Data 57] ABSTRACT 1969 Germany19 53 0144 One or more photoresistors, arranged to detect light passingthrough the film strip, cause varying signal r i "250/219 355/ 2 1 438:voltages, the maximum voltages of which are stored 0 t t t t I l 581Field of Search ..250/219 D, 219 LG, 219 FR, and he ms amanmus s'gnaages to produce a signal corresponding to the format of the film justexamined.

18 Claims, 4 Drawing Figures PATENTEDnm 11 1912 Y 3.699.349

sum 1 or 2 7 a9 Fig-7 INVENTOR RUDOLF PM By HANS-PETER HUBER ARRANGEMENTFOR DETERMINING FRAME LENGTHS ON FILM STRIPS BACKGROUND OF THE INVENTIONtogether the film strip into a long length, which is rolled up, and thento print the negatives in a roll film printer at high speed.Particularly high printing speeds are possible when very printablenegative has at the margin of the film a notch that is in determinedspatial relationship to the negative. It is particularly advantageous tosplice together the film strips before they are developed, because theentire length of the spliced strips can be inexpensively developed incontinuous developers. However, with 35 mm film, perforated along bothedges, several formates are possible: 24 X 36, 24 X 24, and 18 X 24millimeters. When the film is undeveloped, it is impossible to determineof which format the negatives-are. Consequently, it is possible that thedeveloped length of spliced film strips, which is to be printed,contains more than one format. Up to the present time, it has been thepractice to cut out all those negatives not having the most commonformat (24 X 36) and to print these separately, although the necessarycutting and splicing are in themselves expensive and time consuming.

Automatic film notches have been introduced to make format indicatingmarginal notches for the printable negatives using photoelectricscanning, these automatic notchers determine the positions of the framelines between successive negatives. The position of the frame linescannot be determined, however, unless the automatic-notcher hasavailable to it information as to the frame length.

SUMMARY OF THE INVENTION An object of the present invention is anarrangement for determining the frame length of films in an automaticprocessing line for exposed film.

The arrangement of the invention consists essentially of means foradvancing the film along a predetermined film path, at least oneelongated light source arranged on one side of and aligned with the filmpath and extending transversely thereto, the light source having a widthno greater than that of the narrowest frame line, said frame linecomprising the transparent spacing between adjacent frames,phototransducer means, such a photoresistors, arranged on the other sideof the film path opposite the light source for transforming lightpassing through the frame lines into corresponding frame line voltages,and electric evaluation means controlled by the frame line voltages fordetermining the frame length on the film strip in dependence on theframe line voltages.

The arrangement of the invention can be placed in the processing line infront of the automatic notcher, and the format information obtained bythe arrangement sent to the notcher. When the arrangement of theinvention is not used in a processing line, or is used to control aprinter, a detectable format indicating mark can also be made at thebeginning of each film strip.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation,

together with additional objects and advantages thereof, will be bestunderstood from the following description of specific embodiments whenread in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic representation ofthe arrangement of the invention in an automatic processing line;

FIG. 2 is a circuit diagram of a first embodiment of the invention; and

FIGS. 3 and 4 are schematic diagrams of two further embodiments of theinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to FIG. 1, aspool 1 was wound upon it a length of film 2 consisting of a largenumber of individual film strips spliced together. It is assumed thatthe frame format can vary from film strip to film strip, since thestrips'are spliced together before they are developed. The film unwoundfrom the spool 1 passes, first of all, by an arrangement 3, whichdetects the splices between successive film strips, whether by means ofa marginal notch, or by the change in thickness of the film, at thesplice. The film 2 subsequently passes along an extended length of thepath illuminated by a lamp 4. Positioned opposite the light source 4,and extending transversely to the direction of movement of the film is alight admitting aperture 5, the width of which is not greater, andpreferably is less, than the width of the narrowest frame line. The apertures 5 serve as the apparent light sources. Phototransducers 6 arepositioned underneath, and aligned with, the apertures 5. Depending uponthe design of the associated electrical circuitry, a smaller or largernumber of apertures and phototransducers is required. Thephototransducer can be a photomultiplier, a photoelectric cell, aphotoresistor, a photodiode, and the like. In the embodiments to'bedescribed, photoresistors are used for the sake of simplicity. Connectedto the phototransducers is an evaluation circuit the exact design ofwhich depends upon the transducer used.

A slack compensator, having movable guide rollers 8 and 9 is positionedafter the illuminated path to take up and store the length, howeverlong, of a film strip. After advancing through the slack compensator,the film passes by a second splice detector 10, as well as by a formatmarker 11, which makes upon the edge of the film a mark corresponding tothe frame length of that film strip. Two film drive rollers 12 and 13,which positively engage the film 2, are sparked by the splice detectorl0 and started up by the splice detector 3. Finally, the film passesthrough an automatic notcher 14, which is only shown schematically andis completely described in the German Pat. No. 1,285,317. After movingthrough the automatic notcher, the film 2, provided with notches in adetermined relationship with those frames that can be printed, is woundup on a spool 15. A film 2, after having passed through the apparatusshown in FIG. 1, can then be automatically covers circuits based uponthose now to be described that distinguish between more than twoformats.

Connected between the positive and negative lines 16 and 17, is avoltage divider consisting of four photoresistors 18,19,20, and 21, aswell as a fixed resistor 22. The photoresistors 18 to 21 are alignedwith respective aperatures along the film path illuminated by the lamp4, with a spacing of 36 millimeters between successive photoresistors.When the frame format is 24 X 36 millimeters, a frame line is inregistry with each of these photoresistors; and the resulting voltage atthe junction between the series connected photoresistors and theresistor 22 will be indicative of the high degree of transparency of theframe line.

\ The light part of the circuit also has a voltage divider, consistingof four series connected photoresistors 23,24,25, and 26, as well as afixed resistor 27. These photoresistors are aligned with respectiveaperatures 5 along the film path illuminated by the lamp 4, with aspacing of 24 millimeters between successive photoresistors. When theframe format is 24 X 24 millimeters, a frame line is in registry witheach of these photoresistors; and the resulting voltage at the junctionbetween the series connected photoresistors and the resistor 27 willhave its-maximum positive value. It is not essential that thephotoresistors for the different formats have specific spacialrelationship with respect to each-other; it is only essential that theillumination is uniform along the entire path of photoresistors.

One input of an operational amplifier, 28 is connected to the junctionbetween the photoresistor 21 and the fixed resistor 22, theoutput ofthis amplifier being connected by a diode 29 to the gate of a fieldeffect transistor 30. A normally open contact 31a of a relay 31 isconnected between the cathode of the diode 29 and one plate of acapacitor 32, the other plate of which is connected to ground. Anormally open switch 33, controlled by the splice detector 3, is shuntedacross the capacitor 32 to short the latter when closed.

The field effect transistor 30, which acts as an impedance transformer,is connected to the positive line 16 and through a load resistor 34 tothe negative line 17. The second input of the operational amplifier 28is connected to the junction between the load resistor 34 and the fieldeffect transistor 30.

The first input of a further operational amplifier 35' is connected tothe same junction, the other input being connected to a circuit forevaluating the voltage at the junction between the photoresistor 26 andthe fixed resistor 27, this circuit being the same in design as thatjust described for evaluating the voltage at the junction between thephotoresistor 21 and the fixed resistor 22. One input of the operationalamplifier 36 is connected to the .junction between the photoresistor 26and the resistor 27, and the other input is connected to the junctionbetween the field effect transistor 37 and the resistor 38. The outputof the operational amplifier 36 is connected to a diode, the cathode ofwhich is connected to the gate of the field effect transistor 37. Anormally open contact 31b of the relay 31 is connected between thecathode of this diode and one plate of a capacitor 40, the other plateof which is connected to ground. This capacitor is shunted by a normallyopen switch 41 controlled by the splice detector" 3. Theoperationalamplifier 35, which operates as a comparator circuit, has twooutputs, one of which is connected through a relay 42 through a switch43 operated by the splicers of the film strips, and the other of whichis connected to a relay 31 shunted by a capacitor 44.

The circuit just described operates in the following manner. The film 2is unrolled from the spool l and advanced along the film pathilluminated by the lamp 4. The photoresistors 18 to 21 and,23 to 26 aremore or less brightly illuminated, depending upon the transparency ofthe exposed and developed film. The series connection of each groupofphotoresistors ensures that all photoresistors of a group contributeequally to the voltage appearing .at the one input of the operationalamplifiers 28 and 36. If, the average spacing between the highlytransparent frame lines corresponds to the spacing between thephotoresistors of a group, the associated operational amplifiers 28 or36 as the case may be receive a voltage that is appreciably morepositive than is otherwise the case.

ln FlG. 2 it has been assumed that relay 31 is not energized and thatthe switches controlled by the film strip splicers have not beenactuated. Consequently, a

signal is conducted immediately through the diodes 29 and 39 to thegates of the respective field effect transistors 30 and 37. The voltagesappearing at the outputs of the operational amplifiers 28 and 36 are notstored by the capacitors '32 and 40 as long as the relay 31 is notenergized. The voltage appearing at the output of the operationalamplifier 28 is connected through the field effect transistor 30 to thesecond input of this operational amplifier. The operational amplifier 28(or 36) is so designed that when the relay 31 is energized, thecapacitor 32 (or 40) charges until'the voltages at the two inputs of theoperational amplifier .28 (or 36) are equal. The junction between thefield effect transistor 30 and the resistor 34, on the one hand, andthat between the field effect transistor 37 and the resistor 38, on theother hand, enable a low impedance comparison between the voltages onthe capacitors 32 and 40. This comparison is made by the operationalamplifier 35.

It sometimes occurs that a length at the beginning of a film' strip isunexposed, so that at the very beginning there 'is delivered to each ofthe operational amplifiers 28 and 36 a maximum voltage which cannot beexceeded when the, frame lines of the succeeding portion of the filmstrip pass by the photoresistors of the group corresponding to theformat of the film strip. Since both capacitors 32 and 40 store the samemaximum voltage, it is impossible to determine, at the end of the filmstrip, the frame length. To avoid this ambiguity, the operationalamplifier 35 has a further function. If the voltages at its two inputsare equal, this means that there is auniformly transparent length offilm along the illuminated film path. Since the two equal signalsdelivered in this case prevent determination of the frame length, therelay 31 is connected to an output of the amplifier 35, which has novoltage when the two inputs are at equal voltages. The relay 31 remainsunenergized and the two contacts 31a and 31b remain open, so that thecapacitors 32 and 40 cannot be charged, thereby preventing two equalinput voltages from interfering with the determination of the framelength of a film strip. If, however, the two input voltages on theoperational amplifier 35 are not equal, the relay 31 is energized, butonly closes its contacts 31a and 31b after a certain time delay, becauseof the parallel-connected capacitor 44. This delay is of such a lengththat with steady advance of the film, the end of the uniformly darkenedlength of film reaches the end of the series of photoresistors. The twocontacts 31a and 31b then close, and the capacitors 32 and 40 charge tothe maximum voltages appearing at the outputs of the respectiveoperational amplifiers 28 and 36.

If the film 2 is now advanced until the next splice reaches theilluminated film path, there will be stored in each of the capacitors 32and 40 the maximum voltage that can occur between the two splices of thefilm strip from each group of photoresistors. These two maximum voltagevalues are then compared by the operational amplifier 35 to produce ananswer as to which format is present in the film strip that has justpassed through the illuminated film path. The comparator 35 can be sodesigned that, when the voltage across the capacitor 40 is greater thanthat of the capacitor 32, the voltage at the comparator output connectedto the relay 42 is sufficient to cause, when the switch 43 is closed,the relay 42 to be energized. In this way, the unit 11, for example, canbe caused to make a format mark on the beginning of the film strip. Onthe other hand, if the voltage across the capacitor 32 is greater, therelay 42 is not energized. The fact that no format mark appears at thebeginning of the film strip means that the most common kind of format(24 X 36 millimeters) appears onthe strip. The energization of the relay42 can also be used to set the automatic notcher 14 to the less commonformat 24 X 24 millimeters. At the same time, the splice detector 3causes the splice detector to release the film drive rollers 12 and 13,whereby the film strip held in the slack compensator 8 and 9 can bedrawn through the automatic notcher 14.

If a uniformly transparent length appears near the end of a film strip,the voltages across the capacitors 32 and 40 will not appear at therespective inputs of the amplifier 35, since the relay 31 is notenergized. When switch 43 is closed, relay 42 will not be energized evenif it should be. In this case, the relay 42 is controlled by a furthercomparator arrangement, which receives the voltages across thecapacitors 32 and 40 directly, by

bypassing the contacts 31a and 31b.

At the same time that the splice detector 3 is operated by a splice, thecontacts 33 and 41 are closed, thereby discharging the capacitors 32 and40 for the next film strip. This form of the invention requires onlythree apertures, a photoresistor 45 being aligned with the firstaperture. The other two apertures are spaced from the first aperturedistances respectively equal to the possible frame length, the apertureassociated with the photoresistor 46 being spaced 36 millimeters andthat associated with the photoresistor 47 being spaced 24 millimeters.It will be understood that for each additional format to be determined,an extra aperture and photoresistor, appropriately spaced, is added.These photoresistors form voltage dividers with the respective fixedresistors 48,49 and 50 and 51. The resistor 48 has an appreciablysmaller resistance than the resistor 49, and the junction 58 betweenthese two resistors is connected to one input of an operationalamplifier 53, which operates as a store. A diode 55, shunted by anormally open splice switch 54, connects the output of the amplifier 53to one plate of a storage capacitor 56 and to the gate of a field effecttransistor 57. The output of the field effect transistor is connected tothe second input of the operational amplifier 53. The junction betweenthe photoresistor 45 and the resistor 48 is connected to one input of anoperational amplifier 59, which functions as a comparator. The otherinput of the comparator 59 is connected through the field effecttransistor 57 to the storage capacitor 56. The output of the amplifier59 is connected to a relay 60.

The junction 61 and 62 of the voltage dividers 46, 50 and 47,51 areconnected through the normally open contacts a and 60b of the relay 60to respective operational amplifiers 63 and 64. The second inputs ofthese two operational amplifiers are connected to the junction 52 of thevoltage divider 45,48,49. Connected to the outputs of the operationalamplifiers 63 and 64 are respective pulse counters and 66, the stores ofwhich can be compared by a comparator 67. The comparator 67, which isoperated by the splice detector 3, controls a format relay 42 independence upon the result of the comparator.

The circuit just described operates in the following manner. Inconjunction with the arrangement shown in FIG. 1, the voltage appearingat the first, the upper, input of the amplifier 53 is stored in thecapacitor 56, the voltage of which is kept at the maximum valueoccurring during the film strip by its connection through the fieldeffect transistor 57 to the second input of the amplifier 53. Thismaximum voltage across the capacitor 56 is compared by the comparator 59with the voltage at the junction 52. When these two voltages are equal,the comparator 59 delivers a pulse which energizes the relay 60 andcloses the two relay contacts 60a and 60b. By reason of the resistor 48,a pulse is delivered not only when these two voltages are exactly equalor when the voltage appearing at junction 52 is greater, but also withina certain range of equality, which range is determined by the resistor48. It is within this range that the comparator 59 will deliver a pulse,even though the voltage at junction 52, because of variations in grainsize distribution in the frame line, or because of noise level, is asmuch as 3 percent lower than the stored maximum voltage appearing at theother input of the compator 59.

With the contacts 60a and 60b closed, the voltages at the junctions 61and 62 appear at one of the inputs of the respective operationalamplifiers 63 and 6 4. The amplifiers 63 and 64 can now compare thevoltages associated with the frame line (first measurement width)aligned with the photoresistor 45 and the narrow width (secondmeasurement width) of the film strip aligned respectively with thephotoresistors 46 and 47. Since these measurement widths are spacedapart distances corresponding to possible frame lengths, that one of thesecond measurement width which is spaced from the first measurementwidth an amount corresponding to the format of the film strip, willcause a voltage at the junction 61 or 62 at least approximately equal tothat at the junction 52. In other words, this second measurement widthmust be about as transparent as the first. Either the amplifier 63 or 64confirms the equality, or approximate equality, of the two signals anddelivers the pulse to the corresponding counter 65 or 66. If theposition of the photoresistor 46 or 47 is not aligned with a frame line,the transparency of this measurement width is almost certainly less thanif it were a frame line, so that even if the comparison is with amaximum signal (reduced by a factor corresponding to the noise level, nopulse will be delivered. When the film 2 is advanced sufficiently sothat the frame line is moved past the aperture associated with thephotoresistor 45, less light falls on the photoresistor 45, the voltageappearing at the lower input is smaller than that appearing at the upperinput, of amplifier 59, the relay 60 is deenergized, and the contacts60a and 60b open. The junction 61 and 62 are disconnected from theamplifiers 63 and 64 until there again appears at the junction 52 avoltage not appreciably smaller than that stored across the capacitor56. When this is true, the voltages associated with the transparenciesof the measurement widths aligned with the photoresistors 46 and 47 arecompared with the stored value by the amplifiers 63 and 64, and anotherpulse is delivered to the appropriate counter 65 or 66.

The counters 65 and 66 are interrogated at the end of the film strip,the format of the strip being that associated with the counter havingthe largest store. The format relay 42 then delivers a format pulsecorresponding to this format.

In accordance with another embodiment of the invention, when thecomparator 59 confirms an approximate equality at its two inputs, thevoltages at the junction 61 and 62 can be compared with each other,insteadof comparing them with the voltage at the junction 52. Thiscomparison also enables the determination of the distance between twoconsecutive frame lines.

In the embodiment of evaluation circuit shown in FIG. 4, there is onlyone aperture 5 and one photoresistor 68, which is aligned with thisaperture. The lower part of the circuit, connected to the photoresistor68, is the same in design and operation with that shown in FIG. 3, andits components are denoted by the same reference numerals. The output ofthe operational amplifier 59 is connected to two counters 69 and 70,which can be reset to zero by the pulse from the amplifier 59. Incontradistinction to all of the previous embodiments, the film 2 isadvanced stepwise rather than continuously. A pulse generator 71operates a stepping motor 72, which moves the film 2. Since the size ofthe steps can be determined with great exactness, the number of steps isan accurate measurement of the distance the film 2 has been advanced.The pulse generator 71- delivers pulses simultaneously to the twoparallel-connected counters 69 and 70. The counters 69 and 70 are sodesigned that, when reset to zero by the pulse from amplifier 59, theydeliver a pulse to a respective counter 73 or 74, provided that thenumber 8. of pulses delivered to the counters 69 or 70 correspondswithin determined limits to the format associated with the counters 69or 70. If the counters 69 or 70 are set to zero when the total pulsesdelivered to them do not fall within the determined limit for thatcounter, it does not deliver a pulse. The counter 69 is adjusted todeliver a pulse to counter 73 when the total number of pulses from thegenerator 71 corresponds to the format 24 X 36 millimeters, whereas thecounter 70 delivers a pulse to the counter 74 when the total number ofpulses from the generator 71 corresponds to the format 24 X 24millimeters. The two pulse counters 73 and 74 are interrogated by acomparator 75 operated by the splice detector 3, whereupon the unit 76delivers format pulse. I

The circuit just described operates in the following manner. The pulsegenerator 71 steps the stepping motor 72. At the same time, the counters69 and 70 begin from zero with the detection of a new film strip. Thevarying voltage at the junction 58 corresponds to the varyingtransparency of the film strip, and the maximum voltage is stored in thecapacitor 56. If a new maximum value appears at the junction 52, wherebythe voltages at the two inputs of the amplifier 59 are at leastapproximately equal, the amplifier delivers a pulse and resets both ofthe counters 69 and 70 to zero; and this new maximum value is stored inthe capacitor 46. If the number of pulses from the generator 71 lieswithin the limits corresponding to a possible frame length, a pulse isdelivered to a corresponding counter 73 or 74. If the number of pulsesis smaller than the lower limit of the pulse range (frequently the caseat the beginning of a film strip), resetting the counters 69 and 70 tozero does not send a pulse to either of the counters 73 or 74. Onceseveral maximum voltages have been recorded, the voltage across thecapacitor 56 is raised to the full value of the voltage corresponding tothe frame line, and the amplifier 59 delivers a pulse every time thevoltages at its inputs are approximately equal, which is virtually onlywhen a frame line passes by the photoresistor 68. The counters 69 and 70are reset to zero with every pulse from the comparator 59, and thus canbe resetseveral times for a given frame line; but a pulse is deliveredto a counter 73 or 74 only at the leading edge of a frame line, sinceonly at that moment has the counter 69 or 70 received the requirednumber of pulses.

When the splice at the rear end of the film strip approaches the splicedetector 3, the stores of the counter 73 and 74 are compared by theinterrogator 75; and the unit 76 delivers the corresponding formatsignal. At the same time, the switch 54 is closed, and the capacitor 56is discharged to that voltage corresponding to the transparency of thefilm strip aligned with the photoresistor 68 at that moment.

Which of the embodiments described should be used depends upon variousfactors. The large number of apertures, of the embodiment shown in FIG.2, creates illumination problems and difficulties in storing the maximumvalues until the entire film strip has passed through the illuminatedfilm'path and been examined. On the other hand, the evaluation circuitis less expensive to construct, whereas a smaller number of apertures 5requires a more elaborate and expensive evaluation circuit. Theembodiments shown in FIGS. 3 and 4 are designed to make a statisticalevaluation, so that individual errors occuring during the course of asingle film strip, cannot affect the accuracy of the final results.

In accordance with the invention, the evaluation circuit can be alteredin a great many ways. It can produce, for example, an autocorrelationfunction forming an integral of the product of two functions. Theresulting function contains a normal error curve of the frame linedistribution that can be obtained by certain computer operations.

In the evaluation circuits described in connection with FIGS. 2, 3 and4, the relays with their normally open contacts can be replaced bysemi-conductor components, thereby improving the reliability of thecircuit. The circuit diagrams, however, show the more commonly usedmechanical relays, with a view to improving the clarity of the circuits.By reversing the polarity of the voltage dividers having thephototransducers, the

embodiments described can also be used with film resulting from thedevelopment by reversal, the frame lines of which are dark.

It will be understood that each r the elements described above, or twoor more together, may also find a useful application in other types ofcircuits and constructions differing from the types described above.

While the invention has been illustrated and described as embodied inarrangements for determining frame lengths on film strips, it is notintended to be limited to the details shown, since various modificationsand structural changes may be made without departing in any way from thespirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

".What is claimed as new and desired to be protected by Letters Patentis set forth in the appended claims:

1. An arrangement for distinguishing between the lengths of frames on afilm strip, wherein the frames are separatedby frame lines and whereinsaid film strip includes frames of at least two different lengths, saidarrangement comprising, in combination, means for advancing the filmalong a predetermined film path; a plurality of phototransducer meansarranged on one side of said film path; light producing means arrangedon the other side of said film path for generating discrete light beamseach substantially having a width not greater than those of theaforementioned frame lines and directing the same at each of thephototransducer means, the latter means transforming the thus receivedlight beams into corresponding frame line voltages, said transducermeans including, for each different frame length, a group of at leasttwo phototransducers spaced a distance from each other to correspond toa length of one of the frames, the phototransducers associated with apredetermined frame length receiving light beams substantiallyconcurrently only when a film strip having frame lengths correspondingto said predetermined frame length is interposed between said lightproducing means and the associated phototransducers; and electricalevaluation means controlled by said frame line voltages and includingmeans for detecting the groups whose transducers receive the light beamssubstantially concurrently for distinguishing between the frame lengthson said film strip in dependence on said frame line voltages.

2. An arrangement as defined in claim 1, wherein said light producingmeans comprises a respective group of elongated light sources for eachdifferent length of frame, each group comprising at least three lightsources, and a discrete phototransducer being aligned with each lightsource of a group, the phototransducers of the same group beingconnected in series and transforming light passing through said filmstrip into signals that include said frame line voltages when said filmstrip includes frame lengths corresponding to said group.

3. An arrangement as defined in claim 2, wherein said transducers arephotoresistors, whereby the photoresistors of that group correspondingto the frame length detected can achieve the lowest series resistancewhen all the photoresistors of said group receive the light beamssubstantially concurrently in response to passage of a film frame withwhich said group is associated.

4. An arrangement for distinguishing between the lengths of frames on astrip, wherein the frames are separated by frame lines and wherein saidfilm strip includes frames of at least two different lengths, saidarrangement comprising, in combination, means for advancing the filmalong a predetermined film path; a single phototransducer means arrangedon one side of said film path; light producing means arranged to producea light beam having substantially a width not greater than those of theaforementioned frame lines and arranged on the other side of said filmpath for generating a discrete light beam and directing the same at saidphototransducer means, the latter transforming the thus received lightbeam into a corresponding frame line voltage; and electrical evaluationmeans comprising timing means having pulses associated therewith andcontrolledby said frame line voltages for distinguishing between theframe lengths on said film strips in dependence on said frame linevoltages and the time between two successive frame line pulses.

5. An arrangement for determining the length of frames separated byframe lines on a film strip, including, in combination, means foradvancing the film along a predetermined film path; a group of elongatedlight sources for each different length of frame, each said groupcomprising at least three light sources with each arranged to produce alight beam substantially having a width not greater than those of theaforementioned frame lines phototransducer means arranged on the otherside of said film path opposite said light sources for transforminglight passing through said frame lines into corresponding frame linevoltages; electric evaluation means controlled by said frame linevoltages for determining the frame length on said film strip independence on said frame line voltages; a discrete phototransducer meansbeing aligned with each light source of a group, the phototransducermeans of the same said group being connected in series and transl lforming light passing through aid film strip into signal voltages thatinclude said frame line voltages when said film strip includes framelength corresponding to said group; including store means connected toeach group of said phototransducer means'for storing the maximumvoltages of said signal voltages, of which said maximum voltages saidframe line voltages usually are the largest; and comparator means forcomparing between said groups of phototransducer means the storedmaximum voltages to determine the frame line voltage and thereupon fordelivering a frame line length signal at the end of said film strip.

6. An arrangement as defined in claim 5, including store preventingmeans for preventing storage of said maximum voltages when the maximumvoltages of said phototransducer means of at least two groups areapproximately equal.

7. An arrangement as defined in claim 6, including means operated by theend of said film strip for erasing said store means.

8. An arrangement for determining the length of frames separated'byframe lines on a film strip, including, in combination, means foradvancing the film along a predetermined film path; at least one lightsource arranged to produce a light beam having substantially a width notgreater than those of the aforementioned frame lines and arranged on oneside of and aligned with said film path and extending transverselythereto; phototransducer means arranged on the other side of said filmpath opposite said light source for transforming light passing throughsaid frame lines into corresponding frame line voltages; electricevaluation means controlled by said frame line voltages for determiningthe frame length on said film strip in depensociated with said firstphofotransducer, whereby each said further comparator means comparessaid signal voltages associated with said first phototransducer with Isecond comparator means connected to said counter dence on said frameline voltages; wherein said phototransducer means comprises a firstphototransducer and as may further phototransducers as there aredifferent frame lengths to be determined, and an an individual saidlight source for said first phototransducers and each of said furtherphototransducers, each of said further phototransducers being spacedfrom said first phototransducer a distance corresponding to a respectiveframe length, and all of said phototransducers transforming lightpassing through said film strip into signal voltages including saidframe line voltages; means for storing the maximum voltages of saidsignal voltages, of which said maximum voltages said frame line voltagesusually are the largest; first comparator means for comparing saidstored maximum voltages with said signal voltages associated with saidfirst phototransducer; as many pulse generating further comparator meansas there are different frame lengths to determine and controlled by saidfirst comparator means to be connected to said further phototransducersto operate whenever the comparison, by said first comparator means,between said stored maximum voltages and said signal voltages showsapproximate equality, for comparing signal voltages at locations on saidfilm strip spaced at different possible frame lengths from said firstphototransducer.

. 9. An arrangement as defined in claim 8, wherein said first comparatormeans connects said further comparator means to respective ones of saidfurther phototransducers and each said further comparator means isconnected to receive said signal'voltages asmeans for comparing thestore thereof at the end of said film strip and for causing a framelength signal in dependence on that one of said counter means that hasreceived the greater number of pulses.

11. An arrangement as defined in claim 10, including relay means,operated by said first comparator means when said signal voltages andsaid stored maximum voltages are approximately equal, and havingnormally open contacts connected between respective ones of said furtherphototransducers and said further comparator means.

12. An arrangement for determining the length of frames separated byframe lines on a film strip, including, in combination, means foradvancing the film along a predetermined film path; at least one lightsource arranged to produce a light beam having substantially a width notgreater than those of the aforementioned frame lines and arranged on oneside of and aligned with said film path and extending transverselythereto; phototransducer means arranged on the other side of said filmpath opposite said light source for transforming light passing throughsaid frame lines into corresponding frame line voltages; electricevaluation means controlled by said frame line voltages for determiningthe frame length on said film strip in dependence on said frame linevoltages; wherein said phototransducer means transforms the lightpassing through said film strip into signal voltages of which said frameline voltages are usually the maximum, and including means for storingthe maximum voltages of said signal voltages; timing means forgenerating successive pulses; first counter means for each frame formatto be determined connected to said timing means and arranged to receivesaid pulses as well as reset-to-zero pulses, and for delivering afurther pulse upon being re'set-to-zero wherever the interval betweensuccessive reset to zero pulses corresponds to the frame length of arespective counter means; comparator means for comparing said storedmaximum voltages with said signal voltages and for delivering a reset tozero pulse to said first counter means whenever there is approximateequality; timing means for determining the interval between successivesaid pulses.

13. An arrangement as defined in claim 12, including a respective secondcounter means connected to each of said first counter means forreceiving said further pulses therefrom; and means for interrogatingsaid second counter means at the end of said film strip.

greatest number of pulses, whereby said means for storing the maximumvoltages is erased.

15. An arrangement as defined in claim 12, wherein said timing means isa pulse generator.

16. An arrangement for determining the length of frames separated byframe lines on a film strip, including, in combination, means foradvancing the film along a predetermined film path; at least one lightsource arranged to produce a light beam having substantially a width notgreater than those of the aforementioned frame lines and arranged on oneside of and aligned with said film path and extending transverselythereto; phototransducer means arranged on the other side of said filmpath opposite said light source for transforming light passing throughsaid frame lines into corresponding frame line voltages; electricevaluation means controlled by said frame line voltages for determiningthe frame length on said film strip in dependence on said frame linevoltages; including engaging means for positively engaging said filmstrip located downstream of said light source; film strip splicedetector means located upstream of said light source for releasing saidengaging means; and slack compensating means located between said lightsource and engaging means for taking up the length of a film strip.

17. An arrangement for determining the length of frames separated byframe lines on a film strip, including, in combination, means foradvancing the film along a predetermined film path; at least one lightsource arranged to produce a light beam having substantially a width notgreater than those of the aforementioned frame lines and arranged on oneside of and aligned with said film path and extending transverselythereto;

phototransducer means arranged on the other side of said film pathopposite said light source for transforming light passing through saidframe lines into corresponding frame line voltages; electric evaluationmeans controlled by said frame line voltages for determining the framelength on said film strip in dependence on said frame line voltages;including engaging means for positively engaging said film strip; andmarking means located next to said engaging means for marking, independence on said frame length voltage, said film strip near theforward end thereof with a format mark that can be detected.

18. An arrangement for determining the length of frames separated byframe lines on a film strip, including, in combination, means foradvancing the film along a predetermined film path; at least one lightsource arranged to produce a light beam having substantially a width notgreater than those of the aforementioned frame lines and arranged on oneside of and aligned with said film path and extending transverselythereto; phototransducer means arranged on the other side of said filmpath opposite said light source for transforming light passing throughsaid frame lines into corresponding frame line voltages; electricevaluation means controlled by said frame line voltages for determiningthe frame length on said film strip in dependence on said frame linevoltages; including automatic notching means connected to saidevaluation means to notch said film strip in dependence on the framelength.

1. An arrangement for distinguishing between the lengths of frames on afilm strip, wherein the frames are separated by frame lines and whereinsaid film strip includes frames of at least two different lengths, saidarrangement comprising, in combination, means for advancing the filmalong a predetermined film path; a plurality of phototransducer meansarranged on one side of said film path; light producing means arrangedon the other side of said film path for generating discrete light beamseach substantially having a width not greater than those of theaforementioned frame lines and directing the same at each of thephototransducer means, the latter means transforming the thus receivedlight beams into corresponding frame line voltages, said transducermeans including, for each different frame length, a group of at leasttwo phototransducers spaced a distance from each other to correspond toa length of one of the frames, the phototransducers associated with apredetermined frame length receiving light beams substantiallyconcurrently only when a film strip having frame lengths correspondingto said predetermined frame length is interposed between said lightproducing means and the associated phototransducers; and electricalevaluation means controlled by said frame line voltages and includingmeans for detecting the groups whose transducers receive the light beamssubstantially concurrently for distinguishing between the frame lengthson said Film strip in dependence on said frame line voltages.
 2. Anarrangement as defined in claim 1, wherein said light producing meanscomprises a respective group of elongated light sources for eachdifferent length of frame, each group comprising at least three lightsources, and a discrete phototransducer being aligned with each lightsource of a group, the phototransducers of the same group beingconnected in series and transforming light passing through said filmstrip into signals that include said frame line voltages when said filmstrip includes frame lengths corresponding to said group.
 3. Anarrangement as defined in claim 2, wherein said transducers arephotoresistors, whereby the photoresistors of that group correspondingto the frame length detected can achieve the lowest series resistancewhen all the photoresistors of said group receive the light beamssubstantially concurrently in response to passage of a film frame withwhich said group is associated.
 4. An arrangement for distinguishingbetween the lengths of frames on a strip, wherein the frames areseparated by frame lines and wherein said film strip includes frames ofat least two different lengths, said arrangement comprising, incombination, means for advancing the film along a predetermined filmpath; a single phototransducer means arranged on one side of said filmpath; light producing means arranged to produce a light beam havingsubstantially a width not greater than those of the aforementioned framelines and arranged on the other side of said film path for generating adiscrete light beam and directing the same at said phototransducermeans, the latter transforming the thus received light beam into acorresponding frame line voltage; and electrical evaluation meanscomprising timing means having pulses associated therewith andcontrolled by said frame line voltages for distinguishing between theframe lengths on said film strips in dependence on said frame linevoltages and the time between two successive frame line pulses.
 5. Anarrangement for determining the length of frames separated by framelines on a film strip, including, in combination, means for advancingthe film along a predetermined film path; a group of elongated lightsources for each different length of frame, each said group comprisingat least three light sources with each arranged to produce a light beamsubstantially having a width not greater than those of theaforementioned frame lines phototransducer means arranged on the otherside of said film path opposite said light sources for transforminglight passing through said frame lines into corresponding frame linevoltages; electric evaluation means controlled by said frame linevoltages for determining the frame length on said film strip independence on said frame line voltages; a discrete phototransducer meansbeing aligned with each light source of a group, the phototransducermeans of the same said group being connected in series and transforminglight passing through said film strip into signal voltages that includesaid frame line voltages when said film strip includes frame lengthcorresponding to said group; including store means connected to eachgroup of said phototransducer means for storing the maximum voltages ofsaid signal voltages, of which said maximum voltages said frame linevoltages usually are the largest; and comparator means for comparingbetween said groups of phototransducer means the stored maximum voltagesto determine the frame line voltage and thereupon for delivering a frameline length signal at the end of said film strip.
 6. An arrangement asdefined in claim 5, including store preventing means for preventingstorage of said maximum voltages when the maximum voltages of saidphototransducer means of at least two groups are approximately equal. 7.An arrangement as defined in claim 6, including means operated by theend of said film strip for erasing said store means.
 8. An arrangementfor determining the length of frames separated by frame lines on a filmstrip, including, in combination, means for advancing the film along apredetermined film path; at least one light source arranged to produce alight beam having substantially a width not greater than those of theaforementioned frame lines and arranged on one side of and aligned withsaid film path and extending transversely thereto; phototransducer meansarranged on the other side of said film path opposite said light sourcefor transforming light passing through said frame lines intocorresponding frame line voltages; electric evaluation means controlledby said frame line voltages for determining the frame length on saidfilm strip in dependence on said frame line voltages; wherein saidphototransducer means comprises a first phototransducer and as mayfurther phototransducers as there are different frame lengths to bedetermined, and an an individual said light source for said firstphototransducers and each of said further phototransducers, each of saidfurther phototransducers being spaced from said first phototransducer adistance corresponding to a respective frame length, and all of saidphototransducers transforming light passing through said film strip intosignal voltages including said frame line voltages; means for storingthe maximum voltages of said signal voltages, of which said maximumvoltages said frame line voltages usually are the largest; firstcomparator means for comparing said stored maximum voltages with saidsignal voltages associated with said first phototransducer; as manypulse generating further comparator means as there are different framelengths to determine and controlled by said first comparator means to beconnected to said further phototransducers to operate whenever thecomparison, by said first comparator means, between said stored maximumvoltages and said signal voltages shows approximate equality, forcomparing signal voltages at locations on said film strip spaced atdifferent possible frame lengths from said first phototransducer.
 9. Anarrangement as defined in claim 8, wherein said first comparator meansconnects said further comparator means to respective ones of saidfurther phototransducers and each said further comparator means isconnected to receive said signal voltages associated with said firstphototransducer, whereby each said further comparator means comparessaid signal voltages associated with said first phototransducer with thesignal voltages associated with a respective one of said furtherphototransducers to produce a pulse when there is approximate equalitybetween said signal voltages from said first and the respective one ofsaid further phototransducers; and respective counting means connectedto each of said further comparator means for counting the pulsestherefrom.
 10. An arrangement as defined in claim 9, including secondcomparator means connected to said counter means for comparing the storethereof at the end of said film strip and for causing a frame lengthsignal in dependence on that one of said counter means that has receivedthe greater number of pulses.
 11. An arrangement as defined in claim 10,including relay means, operated by said first comparator means when saidsignal voltages and said stored maximum voltages are approximatelyequal, and having normally open contacts connected between respectiveones of said further phototransducers and said further comparator means.12. An arrangement for determining the length of frames separated byframe lines on a film strip, including, in combination, means foradvancing the film along a predetermined film path; at least one lightsource arranged to produce a light beam having substantially a width notgreater than those of the aforementioned frame lines and arranged on oneside of and aligned with said film path and extending transverselythereto; phototransducer means arranged on the other side of said filmpath opposite said light source for transforming light passing throughsaid frame lines into cOrresponding frame line voltages; electricevaluation means controlled by said frame line voltages for determiningthe frame length on said film strip in dependence on said frame linevoltages; wherein said phototransducer means transforms the lightpassing through said film strip into signal voltages of which said frameline voltages are usually the maximum, and including means for storingthe maximum voltages of said signal voltages; timing means forgenerating successive pulses; first counter means for each frame formatto be determined connected to said timing means and arranged to receivesaid pulses as well as reset-to-zero pulses, and for delivering afurther pulse upon being reset-to-zero wherever the interval betweensuccessive reset to zero pulses corresponds to the frame length of arespective counter means; comparator means for comparing said storedmaximum voltages with said signal voltages and for delivering a reset tozero pulse to said first counter means whenever there is approximateequality; timing means for determining the interval between successivesaid pulses.
 13. An arrangement as defined in claim 12, including arespective second counter means connected to each of said first countermeans for receiving said further pulses therefrom; and means forinterrogating said second counter means at the end of said film strip.14. An arrangement as defined in claim 13, including format pulse meansfor delivering a format pulse in dependence on the interrogation of saidsecond counter means showing which of the latter has received thegreatest number of pulses, whereby said means for storing the maximumvoltages is erased.
 15. An arrangement as defined in claim 12, whereinsaid timing means is a pulse generator.
 16. An arrangement fordetermining the length of frames separated by frame lines on a filmstrip, including, in combination, means for advancing the film along apredetermined film path; at least one light source arranged to produce alight beam having substantially a width not greater than those of theaforementioned frame lines and arranged on one side of and aligned withsaid film path and extending transversely thereto; phototransducer meansarranged on the other side of said film path opposite said light sourcefor transforming light passing through said frame lines intocorresponding frame line voltages; electric evaluation means controlledby said frame line voltages for determining the frame length on saidfilm strip in dependence on said frame line voltages; including engagingmeans for positively engaging said film strip located downstream of saidlight source; film strip splice detector means located upstream of saidlight source for releasing said engaging means; and slack compensatingmeans located between said light source and engaging means for taking upthe length of a film strip.
 17. An arrangement for determining thelength of frames separated by frame lines on a film strip, including, incombination, means for advancing the film along a predetermined filmpath; at least one light source arranged to produce a light beam havingsubstantially a width not greater than those of the aforementioned framelines and arranged on one side of and aligned with said film path andextending transversely thereto; phototransducer means arranged on theother side of said film path opposite said light source for transforminglight passing through said frame lines into corresponding frame linevoltages; electric evaluation means controlled by said frame linevoltages for determining the frame length on said film strip independence on said frame line voltages; including engaging means forpositively engaging said film strip; and marking means located next tosaid engaging means for marking, in dependence on said frame lengthvoltage, said film strip near the forward end thereof with a format markthat can be detected.
 18. An arrangement for determining the length offrames separated by frame lines on a film strip, including, incombinatiOn, means for advancing the film along a predetermined filmpath; at least one light source arranged to produce a light beam havingsubstantially a width not greater than those of the aforementioned framelines and arranged on one side of and aligned with said film path andextending transversely thereto; phototransducer means arranged on theother side of said film path opposite said light source for transforminglight passing through said frame lines into corresponding frame linevoltages; electric evaluation means controlled by said frame linevoltages for determining the frame length on said film strip independence on said frame line voltages; including automatic notchingmeans connected to said evaluation means to notch said film strip independence on the frame length.